Apparatus for melting waxy compounds for spraying purposes



June 9, 1953 JEURLING 2,641,676

APPARATUS FOR MELTING WAXY COMPOUNDS FOR SPRAYING PURPOSES Filed July 18, 1950 u M. H. w L r M U xxxxxxggg 1 JTENAJMJH/RL/NG b Hammad J 01-?- RNI",

Patented June 9, 1953 OFFICE APPARATUS FOR MELTING WAXY COM- POUNDS FOR SPRAYING PURPOSES 'Sten A. W. Jeurling, Stockholm, Sweden Application July 18, 1950, Serial No. 174,477 In Sweden June 5, 1950 3 Claims. 1

'.Thls invention relates to an apparatus for melting waxy compounds, such, as Waxy paints sprayed on iron structures as a protection against corrosion, which atroom temperature take a solid, plastic or viscous form, and which are intended to be melted and to be rendered liquid by heating and after that to be fed to a spraying gun or the like in order to be sprayed onsurfaces, which are to be protected against rust or the like. Heated containers for such purposes are previously known in the so-called hot-paint spraying art, but in theseknown, containers the compounds are heated rather slowly and in a direction inwardly from the periphery, since the heat emitting means are arranged around the container. This means that the compound-adjacent the discharge opening of the container communicating with the sprayin sun, which opening for practical reasons is commonly located centrally in the container, will be melted or influenced by the heat last of all, the contents of the container thus tending to cause clogging in the discharge line.

The slow heating and melting of the compounds to be sprayed involves a reduction of the capacity of the spraying plant and to increase this capacity it has been suggested, therefore, to connect the spraying gun by a flexible tube, which is heated preferably by electrical means, with a large-sized pressure receptacle, which also may be electrically heated, so that the supply of fresh unheated compound to the plant would be necessary only at long intervals. In spite of considerable advantages this system is not Very practical because of the diihculty of attaining flexible tubes or" a suitable nature which are capable of withstanding the high temperatures and pressures involved, also the parts incorporated in the spraying plant become diiiicult to manage when moved about.

In accordance with this invention it has been :found that a surprisingly good melting result is obtained by locating a heating element substantially centrally in the container and preferably about or adjacent the tube or tubes, through which the molten compound is discharged to the spraying gun. In addition to the fact that the compound itself serves at leastpartially as heat insulation about the-heat emitting element, the compound is rimarily melted down in that portion, which first discharged container, so that clogging or-the formation ofpiugs thereof are avoided and the discharge of thecompound takes place already before the whole quantity thereof has been melted down or liquefied During the time necessary for discharging 'the'liquefled portion of the compound, further portions thereof are melted down or-rendered liquid until the whole quantity of the mass has been consumed.

The invention may be put into effect invarious ways. Thus the heating element may be an electricheater, or aheat exchanger for a medium having a suitable temperature, as will clearly appear from the following description of certain embodiments of the invention which are illustratedin the accompanying drawing.

In the drawing, Fig. 1 shows an axialsection through an apparatus according to the invention, where the heat-yielding element is constituted-by an electric heating element, while Fig; 2 'showsan axial section through a-more developed-arrangecries a sleeve-shaped electrical heating'element 4 about the, projecting portioni'. The lid 2may be rigidly secured to a spraying guniadapted to discharge the compound heated in the container,

,saidcompound being fed out to the spraying gun through the tube 3. The container I is capable of, being connected to the lid2 in a suitable manner from underneath, as by means of claws 5. The. heating element 4 is connected to a suitable source of current through conductors 6, and is of course insulated from the melting mass.

The apparatus shown inFig. 2may in principle be divided into threemain parts, i. e. a receptacle II for the compound, from which the latter is tobe discharged in a molten state through a central tube [2 projecting into the receptacle, a heat yielding element in the form of a heat exchanger l3 arranged about the portion, of the tube lZentering the receptacle ll, saidheatexchanger. having hot air flowing therethrough, and

an annular air heating chamber I4 arranged around thereceptacle, through which chamber air under pressure ispassed andheated to a high temperature withtheaidof an electrical'heating element I 5, arranged about the inner, wall or. the chamber 14 adjacent to the receptacle. l.l,. ;said heatedair being thenfed. to said heatexchanger. Thus the compoundis here heated in the recep- 3 tacle H both from the outside by the electrical heating elements l5 and centrally by the heat exchanger 53 adjacent the discharge tube l2, to secure an exceedingly rapid and thorough heating of the compound in the receptacle.

It has been found best to invert the compound receptacle ii and provide a lid It at the lower end thereof. The peripheral wall of the receptacle constitutes the inner wall of the air heating chamber it around which the electrical heating element It is wound within said air heating chamber it, which has an outer wall M. The heat exchanger 53 about the discharge tube I2 is located centrally within the receptacle H. The heat exchanger list may be arranged in a number of Ways to cause the hot air to circulate and to flow down to the lowermost end portion or the heat exchanger. In the arrangement illustrated in the drawing, this is achieved by means of helically shaped partitions 87. Preferably, the air heating chamber it and the heat exchanger [3 are rigidly connected to one another through a top structure 58 containing suitable channels IQ for the passage of the hot air from the air heating chamber i l to the heat exchanger 13 and thence further outwardly so as to permit the hot air to be readily conveyed to any desired location. The top structure l8 may be advantageously connected rigidly to the spraying gun, if the dimensions of the apparatus permit such an arrangement. Cold air is supplied into the air heating chamber I l through an inlet 29 from a compressor, and the electrical heating elements l5 are supplied with electric energy in any suitable manner through extensions, not shown, affording a tight pressure-resistant fit.

Some of the air leaving the heat exchanger i3 enters the receptacle H through an aperture 2! in the top structure it to form an internal pressure therein facilitating the discharge of the liquefied compound in the receptacle. A valve 22 with adjusting lever 22' is provided to close the communication between the heat exchanger !3 and the receptacle I l and to open said receptacle to the open air at 23 so that the internal pressure may be reduced before removal of the lid it of the receptacle. The lid i6 is on its inside provided with flanges or projections 24 to establish communication under a solid compound body inserted in the receptacle between the outer and inner side thereof during melting.

It is not necessary to generate the hot air in an air heating chamber arranged about the receptacle i l, as shown in Fig. 2, inasmuch as the hot air can be conveyed into the heat exchanger it from an arbitrary source, but the arrangement shown in Fig. 2 oifers great advantages not only with respect to the requirement of space and manageablenes but also in regard to heat losses within the system. The hot air may be conveyed from the heat exchanger it into the spraying sun through an annular pipe l9 surrounding the extension of tube 12, and further utilized in the spraying process in any desired manner.

obviously be used for the heating of any viscous compound, such as paints, but where the melting of solid or plastic compound is involved, the arrangement involves the problem of facilitating the introduction of the solid or plastic compounds into the receptacle. Pre-cast cylindrical compounds or paint cartridges are known, of a size to fit the receptacle and be readily introduced into it, but these cartridges are unserviceable in the arrangement according to the present invention because of the location of the heat-yielding element. According to the invention, the compound or paint cartridges intended for the apparatus are therefore made with a central hole, into which the discharge tube and the heat-yielding element of the apparatus may be introduced. As indicated in Fig. 3, which shows a perspective view of a paint cartridge 25, the hole 26 may advantageously extend through the whole of the cartridge, so that the location of the cartridge in the receptacle is fixed. If the apparatus for the melt ing of the cartridge is provided with a plurality of discharge tubes and heat-yielding elements, the cartridge will obviously have to be made with a corresponding number of holes.

As will appear from l, the cartridge or filler body is melted down, on being introduced into the apparatus, from the inside out so that the molten and liquid mass collects about the discharge tube and can be delivered immediately to the spraying gun, although the entire cartridge may not be molten. Through radiation, fresh portions of the cartridge are then melted down successively, and these liquefied portions are also collected within the central space in the cartridge. The cartridge may in part thus be sprayed at the same time as it is being melted. the loss of time in the filling of the receptacle becoming consequently very slight. In the apparatus shown in Fig. 2 the cartridge is rapidly melted down both from the inside and the out side by means of heat exchanger is and elec trical element I5 respectively and all the liquid collects near the lid it for further discharge through the tube i2, the projections 25 forming a flowing space under the cartridge.

When a cartridge which has been inserted in the apparatus shown in Fig. 2 is substantially consumed the air pressure within the receptacle is reduced by adjustment of the valve 22, the apparatus is then inverted and the lid I 6 removed. The liquid compound remaining in t. e receptacle, upon insertion of a new cartridge, replacement of the lid and re-inverting of the paratus forms an initial dischargeable volume allowing immediate use of the spray gun.

A number of modifications of the apparatus of the cartridge intended for'the same are obviously conceivable within the scope or" the invention, and the embodiments shown are only to be regarded as examples to illustrate the inventive idea.

I claim:

1. A combined heater for melting and liquefying waxy compounds for spray gun discharge and for heating air to be used in the spraying process, comprising in combination a receptacle for the compound to be heated, an air heating chamber arranged around and on the outside of said receptacle, an electric heating element located within said air heating chamber adjacent the wall of said receptacle and means for passing air through said air heating chamber to said spray gun.

' 2. A combined heater for melting and liquefying waxy compounds for spray gun discharge and for heating air to be used for positively spraying the melted compound; said combined heater comprising a closed receptacle for the compound to be heated, said receptacle having an upwardly projecting discharge tube for the melted compound, an air heating chamber arranged around and on the outside of said receptacle, an electric heating element located within said air heating chamber adjacent the Wall of said receptacle, means for passing air under pressure through said air heating chamber to said spray gun and valve means for admitting heated air under pressure into said receptacle for discharging said compound.

3. A combined heater according to claim 2, further comprising a heat exchanger chamber disposed around said discharge tube within said receptacle and communicating with said air heating chamber so that heated air under pressure passes through said heat exchanger chamber for heating the compound during travel of the latter through said discharge tube, and helical guide means in said heat exchanger chamber to effect swirling of the heated air.

STEN A. W. JEURLING.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Lehmann Aug. 12, 1902 Shoenberg Dec. 1, 1903 Millner June 12, 1923 Kitchen Sept. 22, 1925 Bonoff Nov. 10, 1925 Schenck June 8, 1926 Schneider June 4, 1929 Lockwood Feb. 10, 1931 Long Jan. 8, 1935 Swoboda et al Mar. 19, 1935 Morgan Nov. 11, 1947 Wollner Mar. 29, 1949 Gould Mar. 7, 1950 Moose Mar. 14, 1950 Von Haase Sept. 19, 1950 FOREIGN PATENTS Country Date Switzerland Jan. 2, 1929 Great Britain Apr. 7, 1927 

